Structural Transformations of Ni<inf>1 –</inf><inf>x</inf>Cu<inf> x</inf>Fe<inf>2</inf>O<inf>4</inf> Nanoparticles Depending on the Number of Cu Ions

© 2020, Pleiades Publishing, Ltd. Abstract: Changes in the structure and properties of the Ni1 – xCuxFe2O4 ferrites-spinel magnetic nanoparticles depending on the Cu ion concentration (0 ≤ x ≤ 1.0) have been studied using Mossbauer spectroscopy. It has been found that, with the increasing of the Cu ion concentration, the structure of nanoparticles changes from the structure of reverse spinel (NiFe2O4) to that of mixed spinel (CuFe2O4). It has been shown that the hydrothermal synthesis method makes it possible to obtain single-phase nanoscale particles with a very narrow size distribution and ideal magnetic ordering, which are promising for biomedical applications. The relationship between the distribution of cations on sublattices, the value of the inversion parameter, and the Cu ion concentration has been established

Secondary dolomitization of the Domanik black shales as an indicator of gas-water hydrocarbon-containing fluids upward migration in the Tatarstan territory

© 2020 IOP Publishing Ltd. All rights reserved. The share of unconventional oil reserves is high in Russia and Volga-Ural region, including shale oil reservoirs. It contains around 65% of the total volume of hydrocarbon reserves in region, according to various data. Shale hydrocarbons are widely used in Russia. The main part of the Domaniki oil black shale is confined to carbonate-siliceous carbonaceous complexes of the Domanik horizon of the Francian stage of the Upper Devonian system. According to previous studies in the Domanik formation sedimentary complexes of the Volga-Ural oil and gas province, two types of rocks are distinguished - the Domanikites themselves and Domanikoids. Domanikites contain from 5 to 20% organic matter. Both types of carbonaceous rocks have a practically similar lithological composition. The difference between them lies in variations in siliceous component content and number of authigenic minerals. If content of very fine-grained silica was determined by primary sedimentation factors, then authigenic minerals are indicators of secondary lithogenesis processes. In this work, an attempt is made to compare organic matter content with dolomite mineralization, which is an active agent in mineral formation

Contractions dynamic of "fast" and "slow" rat muscle under spinal shock and modulators of contraction

Aim. To study the dynamics of neuromotor regulation of the contractile function of "fast" and "slow" muscles in rodents during spinal shock by spinal cord transection at the level Th11-Th12. Methods. The experiments were carried out on laboratory rats weighing 140-180 g. The animals were divided into two groups: "Control" (8 rats) and "Spinal shock" (6 rats). The lower leg muscles, m. soleus and m. extensor digitorum longus (m. EDL), were dissected by partially isolating without disrupting the connection with the body's circulatory system. The sciatic nerve was stimulated with single electrical impulses (10 V, 0.5 ms). Contractions of both muscles caused by electrical stimulation of the sciatic nerve before and after the injection of the substances into the femoral artery - tubocurarine (1 mM) or norepinephrine (10 mM) - were recorded in animals of both groups. After spinalization, muscle contractions were re-recorded during electrical stimulation of the sciatic nerve before and 10 minutes after the injection of tubocurarine or noradrenaline into the femoral artery in the same concentrations. Results. After spinalization of the animal, the contraction force of the muscle m. EDL fibers increased to 0.43±0.03 g (p=0.040), but the temporal parameters remained unchanged. M. soleus, on the contrary, showed a decrease in the contraction time to 0.053±0.005 s (p=0.045), and no change in the contraction force was observed under these conditions. Intra-arterial administration of norepinephrine in the control group resulted in an increase of m. soleus contractions up to 1.21±0.17 g (p=0.048), and m. EDL - up to 0.57±0.07 g (p=0.043). The administration of norepinephrine in spinalized animals caused an increase in the contraction of m. soleus up to 1.21±0.09 g (p=0.047), and m. EDL up to 0.66±0.05 g (p=0.043). The blocker of postsynaptic cholinergic receptors tubocurarine administration reduced the force of contraction of both muscle types in both control [m. soleus up to 0.39±0.03 g (p=0.039), m. EDL up to 0.11±0.02 g (p=0.042)] and spinalized [m. soleus up to 0.34±0.05 g (p=0.039), m. EDL up to 0.15±0.04 g (p=0.040)] animals. Conclusion. The data obtained demonstrate the presence of significant differences in the mechanisms of control of contractile activity in the "fast" and "slow" skeletal muscles of warm-blooded animals; the persistence of the similar effect of the basic modulators on the contraction of both muscles with such a striking reaction to spinalization highlights the contribution of neurotrophic control to the functioning of "fast" and "slow" motor units